These huge waves wreak terrific damage when they crash on the shores

These huge waves wreak terrific damage when they crash on the shores of distant lands or continents. Under a perfectly sunny sky and from an apparently calm sea, a wall of water may break twenty or thirty feet high over beaches and waterfronts, crushing houses and drowning unsuspecting residents and bathers in its path.

How are these waves formed? When a submarine earthquake occurs, it is likely to set up a tremendous amount of shock, disturbing the quiet waters of the deep ocean. This disturbance travels to the surface and forms a huge swell in the ocean many miles across. It rolls outward in all directions, and the water lowers in the center as another swell looms up. Thus, a series of concentric swells are formed similar to those made when a coin or small pebble is dropped into a basin of water. The big difference is in the size. Each of the concentric rings of basin water traveling out toward the edge is only about an inch across and less than a quarter of an inch high. The swells in the ocean are sometimes nearly a mile wide and rise to several multiples of ten feet in height.

Many of us have heard about these waves, often referred to by their Japanese name of “tsunami.” For ages they have been dreaded in the Pacific, as no shore has been free from them. An underwater earthquake in the Aleutian Islands could start a swell that would break along the shores and cause severe damage in the southern part of Chile in South America. These waves travel hundreds of miles an hour, and one can understand how they would crash as violent breakers when caused to drag in the shallow waters of a coast.

Nothing was done about tsunamis until after World War II. In 1947 a particularly bad submarine earthquake took place south of the Aleutian Islands. A few hours later, people bathing in the sun along the quiet shores of Hawaii were dashed to death and shore-line property became a mass of shambles because a series of monstrous, breaking swells crashed along the shore and drove far inland. Hundreds of lives were lost in this catastrophe, and millions upon millions of dollars’ worth of damage was done.

1. One surprising aspect of the waves discussed in the passage is the fact that they

(A) are formed in concentric patterns
(B) often strike during clear weather
(C) arise under conditions of cold temperature
(D) are produced by deep swells
(E) may be forecast scientifically

2. The waves discussed in the passage often strike

(A) along the coasts of the Aleutian Islands
(B) in regions outside the area monitored by the Coast and Geodetic Survey
(C) at great distances from their place of origin
(D) at the same time as the occurrence of earthquakes
(E) in areas outside the Pacific region

3. It is believed that the waves are caused by

(A) seismic changes
(B) concentric time belts
(C) atmospheric conditions
(D) underwater earthquakes
(E) storms

4. A possible title for the passage could be

(A) How Submarine Waves Are Formed
(B) How to Locate Submarine Earthquakes
(C) Underwater Earthquakes
(D) “Tsunami” Waves
(E) How to Prevent Submarine Earthquakes